This invention relates generally to igniters made from ceramic materials, which igniters are used in burners on mobile construction equipment, such as a screed on an asphalt paving machine, and more particularly to providing such ceramic materials with a coating that provides the ceramic material with improved resistance to penetration of the ceramic material by moisture or water.
Asphalt pavers use an automatic ignition and safety shutdown system to control ignition and monitor burning of propane on a screed of the paver. Prior art systems employ (among other components) a silicon carbide igniter element which is encased in a ceramic body, with a refractory filler in the ceramic body to hold the lead wires and igniter element in place. The igniter serves two functions in the system. It acts as a resistance heater to ignite the propane fuel and as vehicle for transmission and reception of a high voltage signal used to detect the presence of flame in the burner.
The ceramic prior art materials are extremely porous and absorb moisture readily. Moisture in the unit causes interference with the high voltage detection signal, and in conjunction with the heat of the burner causes corrosion and premature failure of the electrical connection between silicon carbide and the lead wires.
The foregoing illustrates limitations known to exist in present ceramic materials for igniters in screeds for paving machines. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.